This is the sort of thing you can easily
do in your own backyard (subject to local council regulations of course).
It's a simple firing technique used in many ancient cultures across the
globe and popular with potters today.

Difficulty Level: easy Time Required:
half a day

Here's How:

Dig a pit of the appropriate size, depending on the amount of work
to be fired.

Place a bed of dry leaves and twigs and possibly coal, which will
burn slowly, at the bottom of the pit

Place the pottery on top of this.

Carefully sprinkle oxides and carbonates around the pieces (particularly
copper carbonate), which volatilize and result in flashes of color appearing
on the fired work.

Cover the work with more leaves, twigs and dung (if available), building
up a mound over the pieces.

Once the stacking process is finished, light the pile around the edges
and leave to smolder for several hours, or until the next day.

Towards the end of the burning process, bury the pit in earth or sand,
which will cut off the oxygen supply and create a strong reducing atmosphere
inside the mound.

Allow the kiln to cool overnight and open the next day.

Remove excess scum with a wire brush under a running tap.

Tips:

Additions of grog or volcanic ash 'open up' the clay and make it more
resistant to heat shock.

The best color results can be achieved with iron bearing, or red
clays.

Bisque firing the work first helps to prevent shattering and cracking.